1. Exercise and all reported sales made pursuant to a rule 10b5-1 trading plan entered into on June 13, 2012.

2. Common stock as of 07/31/2012 held in a multi-fund 401(k) plan.

3. Non qualified employee stock options originally granted pursuant to the Constellation Energy Group Long Term Incentive Plan. Each Constellation option was converted from the right to purchase 1 share of Constellation common stock to the right to purchase 0.93 shares of Exelon common at a strike price equal to the quotient of the original Constellation strike price and 0.93. This grant became fully vested upon conversion on March 12, 2012. Options expire 10 years from the grant date referenced in Column 1.

5. Restricted stock units originally granted pursuant to the Constellation Energy Group Long Term Incentive Plan and each stock unit was converted to 0.93 stock units of Exelon Corporation on March 12, 2012. Stock units will settle in shares of Exelon common stock on a 1 for 1 basis upon vesting. Award will vest 1/3 in February 2013, 1/3 in February 2014 and 1/3 in February 2015.